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authorDave Hansen <haveblue@us.ibm.com>2005-10-29 18:16:51 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-29 21:40:44 -0700
commit4ca644d970bf2542623228a4624af356d20ca267 (patch)
tree1040782e8799d5531a5ee1d5f1143e26e8781e9d /mm/sparse.c
parented8ece2ec8d3c2031b1a1a0737568bb0d49454e0 (diff)
downloadop-kernel-dev-4ca644d970bf2542623228a4624af356d20ca267.zip
op-kernel-dev-4ca644d970bf2542623228a4624af356d20ca267.tar.gz
[PATCH] memory hotplug prep: __section_nr helper
A little helper that we use in the hotplug code. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/sparse.c')
-rw-r--r--mm/sparse.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/mm/sparse.c b/mm/sparse.c
index 347249a..0d3bd4b 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -72,6 +72,31 @@ static inline int sparse_index_init(unsigned long section_nr, int nid)
}
#endif
+/*
+ * Although written for the SPARSEMEM_EXTREME case, this happens
+ * to also work for the flat array case becase
+ * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
+ */
+int __section_nr(struct mem_section* ms)
+{
+ unsigned long root_nr;
+ struct mem_section* root;
+
+ for (root_nr = 0;
+ root_nr < NR_MEM_SECTIONS;
+ root_nr += SECTIONS_PER_ROOT) {
+ root = __nr_to_section(root_nr);
+
+ if (!root)
+ continue;
+
+ if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
+ break;
+ }
+
+ return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
+}
+
/* Record a memory area against a node. */
void memory_present(int nid, unsigned long start, unsigned long end)
{
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